I would not go with an INTEL core duo INTEL IS MUCH MUCH slower than an AMD dual Core. I would go with AMD do you're research first. HP did a study on intel products since they are partnered with them and foudn that
INTEL DUAL core/core duo's were much slower than there AMD competitors. IT has to do with the way in which the actual processor was layered.

The article is out there and availible to the public I recommend you google it and read the whole thing first. ALso check consumer reports and compare AMD to Intel first.

I personally am not an AMD guy but on this one I would have to say go with AMD.

Also most solo core Mobo's do not support dual core cappabilities. SO if you are really looking to rock it and have the money for the dual core I would spend the extra cash for the AMD dual core and a new mobo to support then Rock that. I think you will be much happier spenidng having spent just a little extra money and it will go a long way. Just make sure the memmory matches and that you wont have to upgrade that as well.